The Dynamic Host Configuration Protocol for Internet Protocol version 6 (DHCPv6) is a network protocol for configuring an Internet Protocol (IP) address, an IP prefix, and/or other configuration information that are required by a DHCPv6 client apparatus operating in an IP version 6 (IPv6) network. DHCPv6 is a stateful address autoconfiguration protocol. In a stateful address configuration process, a DHCPv6 server assigns a complete IPv6 address to a DHCPv6 client apparatus. A Dynamic Host Configuration Protocol (DHCP) unique identifier (DUID) is an identifier for uniquely identifying one DHCPv6 client apparatus. In an interaction process between the DHCPv6 server and the DHCPv6 client apparatus, the DUID is unique and stable, and basically, the DUID of the DHCPv6 client apparatus is unchangeable.
However, in actual application, at least the following problem exists in the foregoing manner. In a network transmission process, the DUID is easy to monitor or steal, and consequently, privacy of the DHCPv6 client apparatus is exposed.